The studies proposed aim at greater understanding of the central phasic activity of REM sleep, which has been investigated heretofore largely in the visual system. Our recent work has demonstrated in the cat, sites of phasic activity in the areas related to auditory functioning in the brainstem, thalamus and cortex, and in the middle ear muscle (MEMA). Using normal and cogenitally blind subjects, we will study the relative amounts, patterns and interrelationships between the phasic discharges in the visual and auditory system in an effort to support the concept that there is no single measure of phasic REMS intensity, and with a view to acquiring greater understanding relative to the unitary vs. multiple character of the center REMS generator. Insofar as prior has demonstrated MEMA to be a low threshold phasic phenomenon, it will be studied to help define whether the sleep onset phase is more properly part of REM or NREM sleep, and to investigate the modifiability of auditory-related phasic activity by perceptual experience. We hope to confirm our earlier studies, which showed correlations between shifts in dream imagery and sensory system-related motor events, with another approach that will employ averaging techniques to demonstrate the receipt of information in predictable sensory cortices and hemispheres at the time of phasic discharge of MEMA and rapid eye movements. We also will utilize our neurophysiological findings concerning MEMA in REMS to study the locations of its inputs in the brainstem, and their relationship to visuomotor REMS generating sites.